Field of the Invention
The invention is concerned with the field of planning, constructing and/or maintaining pipeline systems, in particular extensive and wide-ranging pipeline systems.
The invention relates to a method for planning and/or constructing and/or maintaining a pipeline system, in particular in a power plant, having a plurality of line sections each assigned a set of line parameters including, in particular, a maximum permissible pressure, a maximum permissible temperature and a rated diameter. The invention also relates to a data processing system.
Large technical systems frequently include very extensive, wide-ranging and complicated pipeline systems. Different line parameters are frequently assigned to the individual line sections of such a pipeline system. Such line parameters are, in particular, structural parameters and include, for example, a maximum permissible pressure, a maximum permissible temperature and a rated diameter. Then, the only pipe components installed in the line section must be ones having a physical stress limit that lies above the respective structural parameter.
In a technical article entitled xe2x80x9cProjektierung des EPR [EPR Planning and Design]xe2x80x9d in ATW-International Review of Nuclear Energy, 42nd year (1997), Issue 10xe2x80x94October, pp. 616 to 618, a method is described for fulfilling technical system requirements in the planning of pipe components. In that method the maximum bending radius, the external diameter and the wall thickness of the sections of pipe are determined automatically on the basis of pipeline input values, a control catalog and pipe classes corresponding automatically to a xe2x80x9cboiler formulaxe2x80x9d.
In a book entitled xe2x80x9cDubbel-Taschenbuch fxc3xcr den Maschinenbau [Dubbel""s Mechanical Engineering Manual]xe2x80x9d, Springer Verlag, 1995, 18th Edition, a formula which can be used, inter alia, to calculate a necessary wall thickness from, inter alia, a calculated pressure and an external diameter of a pipe, is given on page K6.
For example, in a newly developed pressurized water reactor, the European Pressurized-water Reactor (EPR), a total of approximately 17,000 sections of pipe with a length of approximately 150 km and with a magnitude on the order of 10,000 pipe components are to be assumed in a reconstructed area alone. During the planning, construction and/or maintenance of such an extensive plant it is easy for errors to occur and the elimination thereof could entail additional costs or a delay. For example, two adjacent pipe components which are associated with a common section of pipe may have different or excessively low loading limits although uniform and/or relatively high structural parameters were provided for the section of pipe. Such an error, that is picked out by way of example from many thousands of possible errors, should be avoided from the outset, additionally in view of the completed safety technology which has been strived for at the EPR. Then the error does not have to be eliminated after a test run or a functional check before the reactor is started up, which would be cost-intensive or time-intensive.
It is accordingly an object of the invention to provide a method for optimizing, speeding up and/or simplifying the planning, constructing and/or maintenance of a pipeline system and a data processing system therefor, which overcome the hereinafore-mentioned disadvantages of the heretofore-known methods and systems of this general type and with which a targeted production or renewal of a line section becomes possible without the possibility of errors occurring in the process.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method for planning and/or constructing and/or maintaining a pipeline system, in particular in a power plant, which comprises assigning a set of line parameters including, in particular, a maximum permissible pressure, a maximum permissible temperature and a rated diameter, to each of a plurality of line sections in a pipeline system; on the basis of a selected set of the line parameters for a line section to be produced or renewed, specifying a material and a wall thickness of an available pipe component sufficient for loading in accordance with the selected set of the line parameters; and generating therefrom a pipe class uniquely defined for the line section, for identifying a sufficiently loadable pipe component for the line section using the pipe class.
The method is based, inter alia, on the fact that it is possible to produce or renew a line section in a targeted, largely error-free manner only if the line section is assigned a pipe class which, on one hand, combines a plurality of similar line sections, i.e. line sections with similar line parameters, and, on the other hand, permits an uniquely defined identification and/or selection of a pipe component. The assignment must take place by taking line parameters, one or more material characteristic variables and one or more pipe component dimensions into account.
The method therefore serves, for example, as a quality-assurance aid for an engineer, fitter or service technician who has to install a new pipe component or a replacement pipe component into a line section.
In accordance with another mode of the invention, the pipe class is generated by virtue of the fact that in each case a strength value and a use priority are assigned to at least one material in a first memory, the external diameter and wall thicknesses of available pipe components are stored in a second memory, and on the basis of the selected set of line parameters for the line section which is to be produced or renewed:
a) the material is specified by virtue of the fact that a material with the highest use priority and the strength value which is assigned to this material are selected from the first memory,
b) the maximum permissible transversal stress is determined for the material,
c) an external diameter is selected from the second memory,
d) a minimum wall thickness is determined from the external diameter and the transversal stress,
e) the wall thickness is specified by virtue of the fact that the next largest wall thickness of an available pipe component is determined from the second memory using the material and the minimum wall thickness, and
f) the pipe class which is uniquely defined for the line section is generated from the selected set of line parameters, the material and the next largest wall thickness.
Through the use of the rule provided according to this embodiment, the assignment, i.e. generation, of the pipe class to the line section is possible in a particularly easy, quick and reliable manner.
The generation of the pipe class and/or of a designation or of a code name for the pipe class, can be carried out, for example, by virtue of the fact that initial letters, abbreviations, code numbers and/or numerical values for the material, the line parameters and/or the next largest wall thickness which is specified are combined to form a pipe class designation.
Instead of the transversal stress, it is also possible, if appropriate, to use a different mechanical stress.
An available pipe component may, for example, be a pipe, in particular a linear pipe, a bent pipe (pipe bend, L element), a branch element (T element), a reducing element or a fitting.
The method is preferably carried out by using an electronic data processing system or a computer. The first and/or second memory is then part of the data processing system or a component of a larger magnetic, optical or electronic memory associated with the data processing system.
The first and/or second memory is preferably implemented in the form of one or more tables in the data processing system.
The use of an electronic data processing system for carrying out the method provides the additional advantage of ensuring that the method can be carried out in a largely automated manner without the involvement of human intelligence. This is advantageous particularly in the planning, construction and/or maintenance of very large and extensive pipeline systems, since errors very easily arise when the method is carried out manually by planning or servicing personnel. In terms of improved quality assurance, the use of an electronic data processing system for carrying out the method is to be preferred over the involvement of human intelligence.
The line parameter sets which are respectively assigned to the line sections can either be entered into the data processing system manually through the use of a data input unit or output from a parameter memory in which the line parameters have previously been stored.
The strength value which is assigned to a material may, for example, be a value for the tensile strength (tearing strength) and/or for the start of flowing (yield point). In particular, in each case a plurality of strength values may be assigned to the material as a function of the temperature.
One or more safety coefficients may be assigned to the material solely, or additionally.
The maximum permissible transversal stress is determined, for example, as a minimum from a first quotient and a second quotient. The first quotient is formed from the tensile strength divided by a first safety coefficient, and the second quotient is formed from the tensile yield strength divided by a second safety coefficient.
In accordance with a further mode of the invention, the minimum wall thickness tmin is determined by using the formula:       t    min    =                              p          A                ·                  D          A                                      2          ·                      σ            perm                    ·                      l            f                          +                  p          A                      +          A      .      
In this case, reference symbol pA designates the maximum permissible pressure in the line section which is to be produced or renewed. Reference symbols DA, "sgr"perm, lf and A stand for the external diameter which has been specified, the maximum permissible transversal stress which has been determined, a longitudinal factor (coefficient of weakening) and a sum of the tolerances which occur (wall thickness supplement).
The formula is preferably evaluated with the aid of a computer. The calculation of the minimum wall thickness, with the aid of a computer, provides the advantage of a precise, continuous and uninterrupted calculation. This is in comparison with a procedure in which constant approximated values for minimum wall thicknesses within specified pressure and temperature intervals are provided in a table and in which an approximated value is read out from the table for a specific temperature and a specific pressure, in order to specify the minimum wall thickness for the line section which is to be produced or renewed. During the precise calculation, a situation in which an unnecessarily enlarged wall thickness is determined as a result of the approximated value is avoided.
In accordance with an added mode of the invention, the component codes for pipe components are stored, ordered according to pipe classes, in a pipe component memory. As a result, the access to a specific pipe component is simplified and speeded up further after a pipe class has been generated, in particular in a largely automated manner in an electronic data processing system, for a line section which is to be renewed or produced.
In accordance with an additional mode of the invention, the pipe classes which are stored in the pipe component memory are regenerated in a uniquely defined way from one or more sets of line parameters, and each pipe component is assigned at least one pipe class.
Through the use of its component code, a pipe component can be ordered in the pipe component memory, in particular under a plurality of pipe classes, and stored.
In accordance with again another mode of the invention, either the pipe class is entered as a new pipe class in the pipe component memory, if that pipe class which has been generated for the selected set of line parameters did not yet exist in the pipe component memory, and a component code of a pipe component which is composed of the specified material and has the specified wall thickness is defined and assigned to this pipe class, or, if the pipe class which has been generated for the selected set of line parameters already existed, a component code which has been stored under this pipe class is selected from the pipe component memory.
This development shows, in particular, that if the pipe class which has been generated for the selected set of line parameters does not yet exist in the pipe component memory, the method operates in a type of learning or build-up mode during which the pipe component memory is gradually built up, i.e. filled with assignments of a component code to form a pipe class. In this learning mode, a component code must also be defined for the pipe component, for which purpose, for example, in the case of the execution of the method through the use of an electronic data processing system, it is possible to provide a software-controlled user input. The program also operates in a type of execution mode if the pipe class which has been generated for the selected set of line parameters already existed. In this case, the data which have been stored in the pipe component memory during the learning mode, for example, are used.
In accordance with again a further mode of the invention, the component code which has either been selected in the execution mode or defined in the learning mode is used, for example, to actuate an automated storage facility which contains pipe components.
As a result, an advantage is obtained which is that the entire process proceeds in a largely automated manner starting from a selected set of line parameters for a line section which is to be produced or renewed and ending with the physical presence of a pipe component at the fitter""s. This occurs without the involvement of human intelligence, especially if the method operates particularly in the execution mode.
In accordance with again an added feature of the invention, the line section which is to be produced or renewed is produced or renewed by using the pipe component that is associated with the selected and/or defined component code.
The method of generating the pipe class according to the invention advantageously ensures that the pipe component is installed in the line section only if it has the same pipe class as that section, and the installation is thus permissible in terms of the maximum expected loading. A pipe class is namely assigned to a line section in a uniquely defined manner according to the method.
The fact that, as described above, one and the same pipe component can be ordered and stored in the pipe component memory under a plurality of pipe classes by virtue of its component code, permits the pipe component, if appropriate, to also be installed in various line sections, in particular in line sections with different pipe classes and thus greatly varying line parameters. However, in the execution of the generation of a pipe class according to the method of the invention, it is ensured in every case that only a sufficiently loadable pipe component is installed.
In accordance with again an additional mode of the invention, the line parameter sets which are respectively assigned to the line sections include, in addition to a maximum permissible pressure, a maximum permissible temperature and a rated diameter, a material type and/or a safety level. The material type may, for example, be a generic term for a plurality of materials. For example, the material type may be xe2x80x9cstainless steelxe2x80x9d, xe2x80x9caustenitic steelxe2x80x9d, xe2x80x9crust-free steelxe2x80x9d or xe2x80x9cnon-ferrous metalxe2x80x9d. The safety level may, for example, contain an item of information indicating how much smaller the maximum permitted transversal stress must be than the strength value assigned to the material. In this case, the safety level contains, as it were, a safety margin which the line section that is to be produced or renewed must have.
In accordance with yet another mode of the invention, a smallest permitted bending radius for the selected pipe component is calculated from the minimum wall thickness which is determined and from the minimum wall-thickness comparison values which are stored. As a result, an additional advantage which is obtained is that when the pipe component that is associated with the component code is installed in the line section, the fitter or installer is provided with the additional information as to how strongly he or she may bend the pipe component, in particular a linear, bent or branched pipe.
In accordance with yet a further mode of the invention, the pipe class which is generated and/or the external diameter which is specified and/or the wall thickness which is specified, are displayed together with the smallest permitted bending radius, on a visual display unit.
In accordance with yet an added mode of the invention, a plurality of alternative materials are taken into account in the generation of the pipe class.
In accordance with yet an additional mode of the invention, initially, for example in method step a), a plurality of materials are selected for which, for example up to method step d), in each case a minimum wall thickness is determined, and that one of these materials which gives rise to the smallest wall thickness is then selected and used as the basis for the further calculation, for example in method steps e) and f).
As a result, it is advantageously ensured, for example, that a higher quality material for which a smaller wall thickness is determined is selected. Under certain circumstances, that can give rise to a saving in terms of material and/or costs.
With the objects of the invention in view there is also provided a data processing system, into which a program for carrying out the method, in particular with its refinements and developments, is loaded.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method for planning, constructing and/or maintaining a pipeline system and a data processing system therefor, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.